'Rh factor' definitions:

Definition of 'Rh factor'

(from WordNet)
noun
A blood group antigen possessed by Rh-positive people; if an Rh-negative person receives a blood transfusion from an Rh-positive person it can result in hemolysis and anemia [syn: rhesus factor, Rh factor, Rh]

Synonyms of 'Rh factor'

From: Moby Thesaurus